WO2022259521A1

WO2022259521A1 - Optical coupling structure and manufacturing method therefor

Info

Publication number: WO2022259521A1
Application number: PCT/JP2021/022299
Authority: WO
Inventors: 光太鹿間; 洋平齊藤; 昇男佐藤
Original assignee: 日本電信電話株式会社
Priority date: 2021-06-11
Filing date: 2021-06-11
Publication date: 2022-12-15
Also published as: JPWO2022259521A1

Abstract

An optical coupling structure (10) according to the present invention comprises: an optical circuit device (12) having an optical circuit core (113) and an overcladding (114); an optical component (12) having a waveguide core (121); and a resin core (131) formed by irradiating a photocurable resin (14) with light. The optical circuit device (11) has a core exposed part (115) in which the optical circuit core (113) is exposed. The resin core (131) is disposed so as to optically couple with the core exposed part (115), and connects to or is in close proximity with an end surface of the waveguide core (121).　The present invention can thereby provide a simple optical coupling structure having favorable optical coupling efficiency.

Description

Optical coupling structure and manufacturing method thereof

The present invention relates to an optical coupling structure that is simple and has good optical coupling efficiency and a manufacturing method thereof.

In order to respond to the rapid increase in Internet traffic in recent years, it is necessary to expand the communication capacity of the data center network. In order to cope with further expansion of transmission capacity and reduction of power consumption, the introduction of optical interconnection that transmits light even in short-to-medium-distance transmission is progressing.

In a typical optical interconnection system, optical transmission such as an optical waveguide or an optical fiber is performed between a light emitting element such as a laser diode (LD) and a light receiving element such as a photodiode (PD) arranged on a printed circuit board. Signal processing is realized by transmission using a medium.

Depending on the transmission method, the optical light emitting element is integrated with an optical modulation element or the like, or connected discretely, and further connected to a driver or the like that performs electrical-to-optical conversion. A configuration including these light emitting elements, light modulating elements, drivers, etc. is mounted as an optical transmitter on an electrical mounting board such as a printed circuit board (PCB). Similarly, the light-receiving element is appropriately integrated with an optical processor or the like, or connected discretely, and further connected with an electric amplifier circuit or the like for performing optical-electrical conversion. A configuration including these light receiving element, optical processor, electric amplifier circuit, etc. is mounted on a printed circuit board as an optical receiver.

Optical interconnection is achieved by mounting an optical transceiver, which integrates an optical transmitter and an optical receiver, in a package or on a printed circuit board and optically connecting it to an optical transmission medium such as an optical fiber. It is Also, depending on the topology, it is realized through a repeater such as an optical switch.

As the light emitting device, the light receiving device, and the light modulation device, semiconductors such as silicon and germanium, III-V group represented by indium phosphide (InP), gallium arsenide (GaAs), indium gallium arsenide (InGaAs), etc. Devices using materials such as semiconductors have been put to practical use. In recent years, along with these elements, optical waveguide type optical transceivers have been developed in which a silicon optical circuit (silicon photonics) having a light propagation mechanism, an indium phosphorous optical circuit, or the like are integrated. In addition to semiconductors, materials such as ferroelectrics such as lithium niobate and polymers may also be used as light modulation elements.

Furthermore, optical functional elements such as planar lightwave circuits made of silica glass are sometimes integrated together with the light emitting elements, light receiving elements, and light modulating elements. Optical functional devices include splitters, wavelength multiplexers/demultiplexers, optical switches, polarization control devices, optical filters, and the like. Hereinafter, devices integrated with light emitting devices, light receiving devices, light modulating devices, optical functional devices, light amplifying devices, etc. having the above light propagation and waveguiding mechanisms will be collectively referred to as optical circuit devices (or simply optical circuits). shall be called. Among optical circuit devices, optical circuit devices using silicon photonics excel in integration, mass production, and compatibility with electrical components, and are attracting attention as key components for realizing next-generation optical interconnection.

One of the representative methods for connecting this optical circuit device and an optical fiber is an optical fiber array integrated with glass or the like having V-grooves formed on one or more end surfaces responsible for optical input/output of the optical circuit. It is a structure that matches and connects with. In this structure, each core of the optical fiber and each core of the optical circuit device are required to be connected with low loss. For this low-loss connection, it is necessary to position (hereinafter referred to as "alignment") and fix the optical circuit device and the optical fiber in submicron units. In this positioning, light is input and output, power is monitored, alignment (optical alignment) is performed, and an adhesive or the like is filled and fixed.

In addition, Non-Patent Document 1 discloses an optical coupling structure using adiabatic coupling. In this optical coupling structure, as shown in FIGS. 17A and 17B, the optical circuit device and the optical waveguide are connected.

The optical circuit device 81 is a silicon photonics chip. An oxide film on a Si substrate is used as an undercladding 812, and an optical circuit made of Si fine wires made up of a Si core 813 is formed thereon. Further, a glass-based material such as quartz glass is deposited on the upper portion of the Si fine wire to serve as an overcladding 814 to confine the Si core 813 .

In adiabatic bonding, as in FIG. 17A, part of the overcladding 814 of the optical circuit device 81 has not been removed or deposited, leaving the core 813 exposed.

The optical waveguide 82 is not an optical fiber but a polymer optical waveguide.

A part of the clad 823 is also removed from the optical waveguide 82, and the core 821 is exposed. Here, as shown in FIG. 17B, the

cores

813 and 821 of the optical circuit device 81 and the optical waveguide 82 are positioned close to each other in the substrate direction.

Here, the Si wire has a structure in which light leaks out by forming a tapered shape or the like in the adiabatic coupling region. At this time, as the light propagates, it is adiabatically transitioned to the polymer core, ideally achieving a coupling efficiency of nearly 100%, thereby achieving highly efficient optical coupling between the optical waveguide and the optical circuit. is realized.

At this time, a resin material is filled around the cores of the optical circuit device 81 and the optical waveguide 82 as an adiabatic coupling clad 83 with an adjusted refractive index. The filling material is made of an adhesive material or the like, and is cured after positioning to integrate the optical circuit device 81 and the optical waveguide (polymer optical waveguide) 82 in an optically coupled state.

However, in the optical coupling structure described above, it is necessary to bring the cores of the optical circuit device and the optical waveguide close to each other for adiabatic coupling. A step of forming a structure is required. Furthermore, since it is necessary to handle the optical circuit or optical waveguide while maintaining the state in which these processes have been performed, there is the problem of additional process load and process restrictions during mounting (for example, process control to prevent dust from adhering). there were.

In addition, when manufacturing an optical coupling structure for an optical circuit device or a polymer optical waveguide by a wafer batch process, the process load can be minimized based on the normal process. However, for example, when using a known optical fiber for an optical waveguide, it is necessary to remove the cladding of the optical fiber, and removing only a portion of the cladding with high precision or reducing the thickness of the cladding is a process burden. becomes a problem because it increases

In order to solve the above-described problems, the optical coupling structure according to the present invention includes an optical circuit device having an optical circuit core and an overcladding, an optical component having a waveguide core, and a photocurable resin irradiated with light. a resin core that is cured by heating, the optical circuit device has an exposed core portion where the optical circuit core is exposed, the resin core is arranged to be optically coupled to the exposed core portion, It is characterized by being connected to or close to the waveguide core.

Further, an optical coupling structure according to the present invention includes an optical circuit device having an optical circuit core and an overcladding, an optical component having a waveguide core, and a resin core which is cured by irradiating a photocurable resin with light. a part of the overcladding on the side where the optical component is arranged is thin, the resin core is arranged to be optically coupled to the optical circuit core under the part of the overcladding, and the waveguide It is characterized by being connected to or close to the core.

A method for manufacturing an optical coupling structure according to the present invention is a method for manufacturing an optical coupling structure including an optical circuit device having an optical circuit core and an overcladding, and an optical component having a waveguide core, wherein the optical circuit In the device, a step of exposing the optical circuit core by removing a part of the overcladding or partially not forming the overcladding to form an exposed core portion; a step of arranging and positioning components, a step of applying uncured photocurable resin to the core exposed portion, and inputting resin curing light from the waveguide core and irradiating the photocurable resin. forming a resin core; and forming a resin clad around the resin core.

A method for manufacturing an optical coupling structure according to the present invention is a method for manufacturing an optical coupling structure including an optical circuit device having an optical circuit core and an overcladding, and an optical component having a waveguide core, wherein the optical circuit In a device, thinning a portion of the overcladding on the side where the optical component is arranged; arranging and positioning the optical circuit device and the optical component; a step of applying a curing photocurable resin; a step of inputting resin curing light from the waveguide core and irradiating the photocurable resin to form a resin core; and forming a resin clad.

A method for manufacturing an optical coupling structure according to the present invention is a method for manufacturing an optical coupling structure including an optical circuit device having an optical circuit core and an overcladding, and an optical component having a waveguide core, wherein the optical circuit In the device, a step of exposing the optical circuit core by removing a part of the overcladding or partially not forming the overcladding to form an exposed core portion; forming a thin clad layer; arranging and positioning the optical circuit device and the optical component; applying an uncured photocurable resin to the thin clad layer; The method includes a step of inputting resin curing light from a waveguide core and irradiating the photocurable resin to form a resin core, and a step of forming a resin clad around the resin core.

According to the present invention, it is possible to provide an optical coupling structure that is simple and has good optical coupling efficiency and a method for manufacturing the same.

FIG. 1A is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the first embodiment of the present invention. FIG. 1B is a schematic front cross-sectional view taken along line IB-IB' showing the configuration of the optical coupling structure according to the first embodiment of the present invention. FIG. 2A is a schematic top cross-sectional view for explaining the method for manufacturing the optical coupling structure according to the first embodiment of the present invention. FIG. 2B is a schematic top cross-sectional view for explaining the method of manufacturing the optical coupling structure according to the first embodiment of the present invention. FIG. 2C is a schematic top cross-sectional view for explaining the method of manufacturing the optical coupling structure according to the first embodiment of the present invention. FIG. 3A is a diagram for explaining the operation of the optical coupling structure according to the first embodiment of the present invention; FIG. 3B is a diagram for explaining the operation of the optical coupling structure according to the first embodiment of the present invention; FIG. 3C is a diagram for explaining the operation of the optical coupling structure according to the first embodiment of the present invention; FIG. 3D is a diagram for explaining the operation of the optical coupling structure according to the first embodiment of the present invention; FIG. 4A is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 4B is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 4C is a side cross-sectional schematic diagram showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 4D is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 5A is a schematic front cross-sectional view taken along line VA-VA' showing the configuration of an optical coupling structure according to a modification of the first embodiment of the present invention. FIG. 5B is a schematic front cross-sectional view taken along VB-VB' showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 5C is a schematic front sectional view taken along line VC-VC' showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 5D is a schematic front cross-sectional view taken along line VD-VD' showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 6A is a schematic front cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. 6B is a schematic front cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention; FIG. FIG. 6C is a front cross-sectional schematic diagram showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 7A is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. 7B is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention; FIG. FIG. 8A is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. 8B is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention; FIG. FIG. 9A is a side cross-sectional schematic diagram showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. 9B is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention; FIG. FIG. 9C is a side cross-sectional schematic diagram showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 9D is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the modification of the first embodiment of the present invention. FIG. 10A is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the second embodiment of the present invention. FIG. 10B is an XB-XB' front sectional schematic diagram showing the configuration of the optical coupling structure according to the second embodiment of the present invention. FIG. 10C is a front cross-sectional schematic diagram showing an example of the configuration of the optical coupling structure according to the second embodiment of the present invention. FIG. 11A is a side cross-sectional schematic diagram showing the configuration of the optical coupling structure according to the third embodiment of the present invention. FIG. 11B is a schematic front cross-sectional view taken along line XIB-XIB' showing the configuration of the optical coupling structure according to the third embodiment of the present invention. FIG. 12 is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the fourth embodiment of the present invention. FIG. 13 is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the fifth embodiment of the present invention. FIG. 14 is a schematic side sectional view showing the configuration of the optical coupling structure according to the sixth embodiment of the present invention. FIG. 15 is a side cross-sectional schematic diagram showing an example of the configuration of the optical coupling structure according to the sixth embodiment of the present invention. FIG. 16A is a schematic side cross-sectional view showing the configuration of the optical coupling structure according to the seventh embodiment of the present invention. FIG. 16B is a schematic top cross-sectional view showing the configuration of the optical coupling structure according to the seventh embodiment of the present invention; FIG. 17A is a side cross-sectional schematic diagram showing a conventional optical coupling structure configuration. FIG. 17B is a schematic cross-sectional view taken along line XVIIB-XVIIB' showing the configuration of a conventional optical coupling structure.

<First Embodiment>
An optical coupling structure according to a first embodiment of the present invention will be described with reference to FIGS. 1A to 9D.

<Configuration of Optical Coupling Structure>
As shown in FIGS. 1A and 1B, the optical coupling structure 10 according to the present embodiment includes an optical circuit device 11, an optical waveguide 12, and an adiabatic coupling portion 13 between the optical circuit device 11 and the optical waveguide 12. Prepare. Here, the input/output end surfaces of the guided light in the optical circuit device 11 and the optical waveguide 12 face each other.

The optical circuit device 11 is a known silicon photonics chip, and includes an undercladding 112 made of a silicon oxide film, an optical circuit core 113 and an overcladding 114 on a silicon substrate 111 in this order. A Si fine line pattern is formed as an optical circuit core 113, and a glass film is deposited as an overcladding 114 to form a confined optical circuit.

Hereinafter, the direction in which light is guided on the horizontal plane (substrate surface) (the X direction in the drawing) is defined as the “longitudinal direction”, the direction perpendicular to the longitudinal direction (the Y direction in the drawing) is defined as the “width direction”, and the horizontal plane (substrate surface) The direction (Z direction in the drawing) perpendicular to the surface) is defined as the thickness direction, the overcladding 114 side is defined as the "upward" direction (Z+ direction) with respect to the optical circuit core 113 of the optical circuit device 11, and the substrate side is defined as the "up" direction (Z+ direction). Let us refer to the “down” direction (Z-direction).

Although not shown in the drawings, the optical light emitting element, the light receiving element, the optical modulation element, the optical functional element, and the optical amplifying element as described in the background are integrated on the optical circuit.

In addition, the optical circuit device 11 is integrated in a hybrid manner with an optical transmission element, an optical modulation element, or the like made of a compound semiconductor or the like, as required. The thickness of the waveguide substrate 111 is, for example, 625 μm, which is the standard silicon wafer thickness.

The silicon photonics chip does not have the overcladding 114 in the vicinity of at least one connection end surface, and has a portion (hereinafter referred to as "core exposed portion") 115 where the optical circuit core 113 is exposed. The core exposed portion can be produced by partially removing the overcladding 114 by etching or the like after forming the overcladding 114 entirely. Alternatively, it can be fabricated by partially masking and forming the overcladding 114 .

The length of the core exposed portion 115 in the core longitudinal direction (X direction) is approximately 1 mm. As will be described later, this can be appropriately changed according to the coupling length required for adiabatic coupling, and can be appropriately set to about 0.1 mm to 3 mm in consideration of the refractive index difference, positioning tolerance, and the like.

The silicon wire (optical circuit core) 113 has a tapered shape at the core exposed portion 115 . The tapered shape is a shape in which the width of the fine line becomes thinner from the optical circuit device 11 side toward the optical waveguide 12 side along the longitudinal direction (X direction) like a known spot size converter (SSC). is used. The tapered shape may be a non-linear tapered shape, a multistage tapered shape, or an SSC structure such as a segmented SSC, which consists of a discontinuous body of a Si core and a glass material.

Here, an example in which the tip of the silicon wire (optical circuit core) 113 and the end face of the optical waveguide 12 are arranged apart is shown, but the tip of the silicon wire and the end face of the optical waveguide 12 may be in contact. Guided light leaks from the tapered portion of the silicon wire, and the silicon wire (optical circuit core) 113 and the optical waveguide 12 are optically coupled.

The optical waveguide 12 has a waveguide core 121 and a waveguide clad 122 . In this embodiment, the optical waveguide 12 uses a known single-mode fiber (SMF) made of silica glass. The SMF has a core (hereinafter also referred to as "fiber core") 121 and a clad (hereinafter also referred to as "fiber clad") 122, the core diameter is approximately 8.2 μm, and the relative refractive index difference is 0. .3%.

The heat-insulating coupling portion 13 includes a core (hereinafter referred to as “resin core”) 131 made of photocurable resin and a clad (hereinafter referred to as “resin clad”) 132 arranged around the resin core 131 . .

The resin core 131 is formed in the core longitudinal direction (X direction) so as to be in contact with the end face of the core 121 of the optical fiber that is the optical waveguide 12, and is close to the core of the optical circuit.

In the present embodiment, an example in which the resin core 131 is formed in contact with the upper surface of the exposed core portion 115 is shown. Resin core 131 may be arranged so as to be coupled with guided light leaking from core exposed portion 115 . For example, it is formed on or near the upper surface of the tapered portion of the core exposed portion 115 .

In the optical coupling structure 10, a plurality of optical fibers 12 and a plurality of optical circuit devices 11 are arranged. be done.

A photocurable resin is a known resin that reacts to a specific wavelength and undergoes a curing reaction. Materials known as photoresists may be used. The curing wavelength can be arbitrarily designed by adding an initiator, a dye, or the like, and wavelengths from ultraviolet light to visible light can be used.

The resin clad 132 is a resin having a lower refractive index than the resin core 131 in the signal wavelength band, and is filled around the resin core 131 . Known acrylic resins, epoxy resins, silicone resins, urethane resins, oxetane resins, and the like can be used as the resin clad material, and halogen-substituted compounds such as fluorination may be used as appropriate to adjust the refractive index.

<Method for manufacturing optical coupling structure>
An example of a method for manufacturing an optical coupling structure according to this embodiment will be described with reference to FIGS. 2A to 2C.

First, in the optical circuit device 11 , the clad is partially removed to expose the optical circuit core 113 and form the exposed core portion 115 .

Next, the optical circuit device 11 and the optical waveguide (optical fiber) 12 are arranged and positioned, and the uncured photocurable resin 14 is applied to the exposed core portion 115 of the optical circuit device 11 . Next, resin curing light 15 is input from the optical fiber core 121 (FIG. 2A).

Any input method can be used as an input method for the resin curing light 15. For example, input can be performed by connecting a resin curing light source from the end face opposite to the connection end face of the optical fiber.

The resin curing light 15 is emitted from the end of the optical fiber core 121 (connection end face) after propagating through the core 121 of the optical fiber. A curing reaction of the photocurable resin 14 is induced by irradiating the photocurable resin with the resin curing light 15 .

Next, a resin core 131 is formed in the longitudinal direction (X direction) so as to be in contact with the optical fiber core 121 (Fig. 2B).

At this time, the cross section of the resin core 131 in the core longitudinal direction (X direction) is formed to have a shape similar to the mode distribution of the resin curing light 15 from the optical fiber core 121 . For example, a Gaussian beam has a shape close to a circular cross section. Alternatively, the mode shape may result in an elliptical shape.

Also, when the mode distribution of the resin curing light 15 extends to a structure such as the optical circuit board 111, the mode distribution is formed in a circular cross-sectional shape with a part missing.

After that, the resin clad 132 material is filled around the resin core 131 in the core exposed portion 115 of the optical circuit and cured to form the resin clad 132 (FIG. 2C). A photocurable resin or a thermosetting resin may be used for the material of the resin clad 132 .

Here, before filling the resin clad 132 material, the uncured portion of the photocurable resin 14 is removed.

Alternatively, if a refractive index difference can be formed in a photocurable resin cured by resin characteristics, the photocurable resin can be used as a resin clad material without removing the uncured portion of the photocurable resin. can.

For example, a refractive index difference may be formed in the cured photocurable resin by using a difference in curing wavelength or by using two-photon absorption and one-photon absorption. Alternatively, a resin having a different refractive index after being cured by photocuring or heat curing may be used. Moreover, the photocurable resin may be a mixture of two or more different resin materials, or may be used so as to form a copolymer after curing.

<Operation of Optical Coupling Structure>
3A to 3D respectively show the propagation modes in the IIIA-IIIA', IIIB-IIIB', IIIC-IIIC', and IIID-IIID' cross sections in FIG. 2C. These propagation modes are calculated by the FDTD (Finite-difference-time-domain) method.

Assuming that a normal silicon photonics chip and SMF are used, the signal wavelength is 1.55 μm, the refractive index of the resin core 131 is 1.5, and the refractive index of the adiabatic coupling clad is 1.46 at the same wavelength.

In the IIIA-IIIA' cross section on the silicon photonics chip side, the light propagation mode is confined in the Si wire (Fig. 3A). In the IIIB-IIIB' section, the confinement of the light propagation mode expands towards the resin core 131 above the Si wire (FIG. 3B). At the IIIC-IIIC' section, most of the light propagation modes are confined in the resin core 131 (Fig. 3C). In the IIID-IIID' section, the light propagation mode is confined in the resin core 131 (Fig. 3D).

Thus, the propagation mode of light leaks to the outside and transitions to the resin core 131 as it propagates in the longitudinal direction (X direction) due to the tapered structure of the Si fine wire. The guided light is completely transferred to the resin core 131 by propagating in the longitudinal direction (X direction) over a certain length. According to the calculations above, 95% of the guided light propagates through the resin core 131 . Light from the resin core 131 is then coupled with the optical fiber core 121 .

As described above, according to the present embodiment, it is possible to optically couple an optical fiber and a silicon photonics chip with low loss. Since the above operation is reversible, it operates in the same way even if the input/output pair is changed.

<effect>
According to the optical coupling structure according to the present embodiment, it is not necessary to remove the clad partially from one of the optical waveguides in the conventional method, or to form a structure having no clad partially. Optical coupling can be achieved by adiabatic coupling with the resin core 131 formed in .

Especially when an optical fiber is used as an optical waveguide in the conventional method, it is difficult to adiabatically couple the optical fiber and the optical circuit device 11 because of the heavy load of the process of partially removing the clad. According to this embodiment, by forming the resin core 131 from the end face of the optical fiber, the adiabatic coupling of the optical circuit device 11 via the resin core 131 can be realized.

In addition, the adiabatic coupling can relax the positioning accuracy of the optical waveguide core and the optical circuit core 113 compared to the conventional butt connection, so it is possible to achieve optical coupling easily and highly efficiently.

Furthermore, the optical coupling structure according to this embodiment has the following effects.

Adiabatic coupling utilizes the property that light transitions to the high refractive index side. Therefore, in order to efficiently cause optical transition, it was necessary to set the refractive index of the core of the optical waveguide to be connected to be larger than that of the oxide film, which is the undercladding of the optical circuit board, by a certain amount or more.

This was a factor limiting the optical waveguide materials to be connected. For example, when using a waveguide material, such as a polymer waveguide, in which the core material and the clad material can be relatively freely selected, the refractive index of the core of the optical waveguide can be relatively freely selected.

However, in known glass optical fibers, the clad is made of silica glass, and the core is made of a material with a slightly higher refractive index than silica glass (for example, a relative refractive index difference of 0.3% to 2%). Therefore, since there is only a slight difference in refractive index between the core material and the undercladding (oxide film), it has been difficult to set the refractive index of the core of the optical waveguide (optical fiber) higher than that of the undercladding by a certain amount or more.

Since the refractive index of the optical fiber is very close to that of the undercladding (oxide film), the refractive index of the optical fiber is set to about 1.5 so that the difference between the refractive index of the optical fiber and that of the undercladding (oxide film) becomes large. It is difficult to do so even by adding a dopant to quartz glass. Therefore, it has been difficult to realize adiabatic coupling with optical fibers in the conventional structure.

In the present embodiment, it is only necessary to form a resin core having an appropriate refractive index from the end face of the optical fiber in a post-process and fill it with a clad resin. Therefore, there is no need to adjust the core refractive index of the optical waveguide (optical fiber), and only by adjusting the core refractive index of the photocurable resin, adiabatic coupling via the resin core results in low loss between the optical fiber and the optical circuit. optical coupling can be realized.

In addition, in the conventional structure, when the optical circuit device and the optical waveguide core are mounted close to or in contact with each other, it is necessary to control the position in the thickness direction with very high precision. It was necessary to control the process at a high level.

For example, when arranging an optical waveguide core so as to be in contact with a core of an optical circuit device, if the cores are excessively pressed against each other, one of the cores may be damaged. I needed it.

In the present embodiment, since the resin core can be formed by simply bringing the thin wire of the optical circuit device core and the core of the optical waveguide (optical fiber) close to each other, the optical waveguide and the core of the optical circuit device or the cores of the optical circuit devices The pressing process becomes unnecessary, and the process control conditions can be relaxed.

<Modification>
An optical coupling structure according to a modification of this embodiment will be described with reference to FIGS. 4A to 9D.

In the optical coupling structure according to this modification, as shown in FIGS. 4A to 4D, the resin core 131 is formed in part of the core exposed portion 115 of the optical circuit device 11. FIG.

The resin core 131 is formed so that the lower surface of the resin core 131 is in contact with the upper surface of the core exposed portion 115, as shown in FIGS. 4A and 5A. The resin core 131 may be spaced apart from the end surface of the overcladding 114 .

Alternatively, as shown in FIGS. 4B and 5B, the optical circuit core 113 may be partially embedded in the resin core 131 .

In this configuration, while the shape of the mode propagating in the resin core 131 is deformed from that of the Gaussian beam, as shown in FIG. Optical coupling can be performed with high efficiency without impairing the coupling efficiency even when the position of the core is displaced.

Alternatively, as shown in FIGS. 4C and 5C, the optical circuit core 113 may be entirely embedded in the resin core 131 . Here, the shape of the cross section of the resin core 131 is circular with the lower part missing, and the cross-sectional area is smaller than in the case of a circular shape.

In this configuration, it is calculated that if the cross-sectional area of the resin core 131 is equal to or larger than the area of a semicircle, the FDTD can achieve low-loss adiabatic coupling without impairing the coupling efficiency.

Also, as shown in FIGS. 4D and 5D, the resin core 131 and the optical circuit core 113 may be arranged separately without being in contact with each other. It is calculated by FDTD that, in this configuration, the clad 132 of the adiabatic coupling portion 13 has a small refractive index, so that optical coupling can be similarly achieved.

Here, the distance between the bottom surface of the resin core 131 and the top surface of the optical circuit core 113 must be shorter than the thickness of the undercladding 112 . Here, the thickness of the under clad 112 is desirably within 3 μm.

In the optical coupling structure according to this embodiment, the effect is obtained not only when the resin core 131 and the optical circuit core 113 are arranged in contact with each other, but also when the resin core 131 and the optical circuit core 113 are arranged apart from each other. Play. The distance between the resin core 131 and the optical circuit core 113 should be shorter than the thickness of the undercladding 112 . In other words, it is sufficient that the resin core 131 and the optical circuit core 113 are spaced apart from each other within the range of optical coupling.

Further, even if the resin core 131 and the optical circuit core 113 are slightly misaligned in the waveguide width direction (Y direction), the guided light can be sufficiently coupled.

For example, in FDTD, even if the resin core 131 and the optical circuit core 113 are misaligned by about 2 μm in the waveguide width direction (Y direction), if the distance in the longitudinal direction (X direction) is long, the guided light will be different from the resin core 131 and the optical circuit. Transitions to and from core 113 are calculated. Also, as shown in FIGS. 5B and 5C, the greater the contact area (region) between the resin core 131 and the optical circuit core 113, the greater the tolerance to the displacement between the resin core 131 and the optical circuit core 113. FIG.

Therefore, the arrangement of the resin core 131 and the optical circuit core 113 shown in FIGS. 5A to 5D should be appropriately designed in consideration of the positioning accuracy, the length of the core in the longitudinal direction (X direction), the difference in refractive index of each core, and the like. Just do it.

In the optical coupling structure according to this modified example, the cross-sectional shape of the resin core 131 is not limited to a circular cross-section, and may be any cross-sectional shape that allows adiabatic coupling. For example, it may be elliptical as shown in FIG. 6A, nearly rectangular as shown in FIG. 6B, or as shown in FIG. 6C. These shapes can be arbitrarily designed according to the mode distribution of the resin curing light 15 from the optical waveguide 12, the input power of the curing light, the wavelength of the curing light, and the degree of curing of the resin.

Further, the core diameter of the resin core 131 is not necessarily the same as the core diameter of the optical waveguide 12, and may be larger than the core diameter of the optical waveguide 12 as shown in FIG. 7A. It may be smaller than the core diameter of the optical waveguide 12 . These diameters can be arbitrarily designed according to the mode distribution of the resin curing light 15 from the optical waveguide 12, the input power of the curing light, the wavelength of the curing light, and the degree of curing of the resin.

In the optical coupling structure according to this modified example, an example in which the end face of the optical waveguide 12 and the end face of the optical circuit device 11 are in contact with each other is shown. good.

In this case, the resin core 131 and the resin clad 132 connect the optical circuit device 11 and the optical waveguide 12 . Here, the optical circuit device 11 and the optical waveguide 12 may be fixedly connected with an adhesive or the like.

Also, in the optical coupling structure according to this modified example, an example in which the end face of the optical waveguide 12 and the end face of the optical circuit device 11 are arranged so as to face each other in parallel has been shown, but the present invention is not limited to this. For example, as shown in FIG. 8B, the end face of the optical waveguide 12 may be arranged so as to be inclined with respect to the end face of the optical waveguide 12, and the resin core 131 may also be arranged so as to be inclined with respect to the traveling direction. It suffices if an overlapping portion between the core of the optical circuit device 11 and the core required for adiabatic coupling can be secured.

In the optical coupling structure according to this modified example, an example in which the side cross-sectional shape of the resin core 131 is rectangular has been shown, but it is not limited to this. As shown in FIG. 9A, the resin core 131 may be formed to cover the overclad 114 in the vicinity of the end face of the overclad 114 or may be formed to contact the side surface of the overclad 114 .

Also, as shown in FIGS. 9B and 9C, the side cross-sectional shape of the resin core 131 may be tapered along the longitudinal direction (X direction).

In addition, as shown in FIG. 9D, the resin core 131 may be terminated apart from the end surface of the overclad 114 in the longitudinal direction (X direction) as long as the heat insulating connection can be secured. may be pointed.

In the present embodiment and modifications, other than silicon photonics, for example, an InP integrated circuit, quartz PLC, LN circuit, etc. may be used as the optical circuit device 11 .

Also, an example using a general SMF for communication wavelengths as an optical fiber has been shown, but the type of optical fiber may be changed as necessary. For example, an optical fiber with a high refractive index difference, known as high NA fiber, may be used.

Also, in the present embodiment, the optical waveguide is exemplified by connection with an optical fiber, but as will be described later, another optical waveguide device such as a polymer waveguide may be used instead of the optical fiber. Also, the present invention can be similarly applied to the connection between optical circuit devices.

Although not shown, a resin such as an adhesive can be additionally used as appropriate for integration of each part. For example, in addition to the adiabatic coupling clad resin, an adhesive may be filled between the end surfaces of the optical waveguide device and the optical circuit device to fix them.

Also, as will be described later, the positioning structure shown in FIG. 2A may be used in combination with any known positioning structure. These are the same for the embodiments described later.

In addition, the end face of the optical circuit or optical waveguide is polished as necessary.

<Second Embodiment>
An optical coupling structure according to a second embodiment of the present invention will be described with reference to FIGS. 10A and 10B.

<Configuration of Optical Coupling Structure>
The optical coupling structure 20 according to the present embodiment differs from the first embodiment in the configuration of the exposed core portion 115 . Other configurations are the same as in the first embodiment, the optical circuit device is a silicon photonics chip, and the optical waveguide is SMF.

In the optical coupling structure 20, as shown in FIGS. 10A and 10B, the optical circuit core is covered with a thin protective clad layer 116 at the core exposed portion 115 of the optical circuit device 11. FIG.

The protective clad layer 116 can be formed, for example, by partially controlling the removal amount of the overcladding 114 so that the optical circuit core 113 is not completely exposed when the overcladding is removed.

Alternatively, after forming the overcladding 114, CMP polishing is performed, and after forming a thin etching protection film such as SiN on a part, the overcladding is again formed as a protective cladding layer 116, and only a part is etched. can also be fabricated, and the same structure can be realized by combining known process techniques such as those described above.

Thus, in the optical coupling structure 20, a part of the overcladding on the side where the optical component 12 is arranged is thin (protective clad layer 116), and the resin core 131 is thicker than a part of the overcladding (protective clad layer 116). It is arranged so as to be optically coupled with the optical circuit core 113 below.

The photocurable resin core 131 is formed by the resin curing light 15 of the optical fiber, which is the optical waveguide 12. The resin core 131 is arranged above the clad protective layer, and the resin core 131 is filled with the resin clad 132. It is

At this time, the refractive index of the protective clad layer 116 is preferably approximately the same as the refractive index of the resin clad 132 or the refractive index of the underclad 112 in order to efficiently achieve adiabatic coupling.

For example, if the refractive index of the resin clad 132 and the refractive index of the protective clad layer 116 are the same, it is optically equivalent to when there is a slight distance between the resin core 131 and the optical circuit core 113 as shown in FIG. 5D. can be regarded as As a result, the light from the optical circuit core 113 can adiabatically transit to the resin core 131 and can be optically coupled with high efficiency.

Here, in order to suppress light transition to the Si substrate 111 with a high refractive index, the thickness of the protective clad layer 116 must be smaller than the thickness of the undercladding 112 layer. In particular, in order to ensure high coupling efficiency, the thickness of the protective clad layer 116 is preferably less than half the thickness of the undercladding layer 112 .

Also, as described above, the protective clad layer 116 may be formed of a material similar to the silicon oxide film 112, which is the underclad, and an etching protective film 116_2 such as SiN may be provided thereon (FIG. 10C). In this case, it is preferable that the thickness of the etching protection film is less than the signal wavelength (for example, about several nanometers) so that the guided light is not affected by the etching protection film.

<effect>
According to the optical coupling structure according to this embodiment, the same effects as those of the first embodiment can be obtained. Specifically, it is possible to achieve highly efficient adiabatic coupling without the need for the conventional method of partially removing the clad from one of the optical waveguides or forming a film with a partially clad-free structure. , optical coupling can be realized by adiabatic coupling with a resin core formed in a post-process.

Further, in the present embodiment, the adiabatic coupling between the resin core and the optical circuit device can be realized only by adjusting the core refractive index of the photocurable resin without adjusting the core refractive index of the optical waveguide (optical fiber). It can also be applied to known optical fibers.

In addition, in the present embodiment, the process of pressing the optical waveguide and the optical circuit core or between the optical circuit cores, which is required in the conventional adiabatic coupling, is not required by using the resin core, thereby easing the process control conditions. can.

Furthermore, in this embodiment, handling in the mounting process and storage process on the optical circuit side is facilitated. That is, in the manufacturing process of the configuration in which the optical circuit core is exposed in the first embodiment, a cleaning process for preventing dust from adhering to the optical circuit core and removing dust is required. In addition, since the optical circuit core is exposed to the air, it is necessary to strictly control deterioration around the core, for example, humidity control and storage atmosphere.

According to the optical coupling structure according to the present embodiment, the optical circuit core and the resin core are not in direct contact with each other. While the core needs to be lengthened, the storage, cleaning, and mounting process conditions accompanying the exposure of the optical circuit core can be relaxed.

It should be noted that the present embodiment can be similarly applied to various modifications and configuration changes in the first embodiment. For example, it can be applied to optical coupling between optical circuit devices other than optical circuit devices and optical waveguides.

In addition to optical fibers, various optical waveguides such as polymer optical waveguides and glass optical waveguides can be used as optical waveguides.

In addition, as an optical circuit device, it can be applied to various optical circuit devices other than silicon photonics.

In addition, it can be similarly applied to the various modifications described above and modifications of structures that can be analogized.

<Third Embodiment>
An optical coupling structure according to a third embodiment of the present invention will be described with reference to FIGS. 11A and 11B.

<Configuration of Optical Coupling Structure>
The optical coupling structure 30 according to this embodiment differs from the first embodiment in the configuration of the optical waveguide. Other configurations are substantially the same as in the first embodiment, and the optical waveguide device is a silicon photonics chip.

In the optical coupling structure 30, a high NA fiber is used as the optical waveguide 12 shown in FIGS. 11A and 11B. A high NA fiber has, for example, a core diameter of 3 μm, which is smaller than that of an SMF, and a Δ of about 2%.

The resin core 131 is formed by the resin curing light 15 from the high NA fiber 12, the resin core 131 is arranged on the upper surface of the core exposed portion 115 of the optical circuit, and the resin core 131 is filled with the resin clad 132. there is Alternatively, when the core exposed portion 115 has a clad protective layer, the resin core 131 is arranged on the upper surface thereof.

Since the diameter of the core 121 of the high NA fiber 12 is smaller than that of the SMF, the cross-sectional area of the resin core 131 formed from the end faces is smaller than those of the first and second embodiments. For example, if it is formed with the same diameter as the core 121 of the high NA fiber 12, the resin core 131 has a diameter of about 3 μmΦ.

The resin core 131 and the resin clad 132 can be appropriately set in consideration of the diameter of the resin core 131 so as to realize appropriate thermal insulation coupling.

Furthermore, in the present embodiment, since the resin core diameter is small, the mode diameter of light propagating through the resin core is also small. Therefore, the distance between the center positions of the mode diameters of the resin core and the optical circuit core with respect to the substrate thickness direction (Z direction) is smaller than when the SMF is used. As a result, optical transition due to adiabatic coupling occurs more easily, so even if the core in the longitudinal direction (X direction) required for adiabatic coupling is short, optical coupling can be realized with sufficiently high efficiency.

For example, as shown in FIG. 11B, even when the resin core 131 and the optical circuit core 113 are not in contact with each other, the distance between the centers of the mode diameters of the resin core 131 and the optical circuit core 113 is small. Even if the height accuracy of the position is low (even if the resin core 131 and the optical circuit core 113 are separated), good optical coupling can be achieved.

It should be noted that this embodiment can be similarly applied to various modifications and configuration changes in the first and second embodiments. For example, it can be applied to optical coupling between optical circuit devices other than optical circuit devices and optical waveguides.

In addition to optical fibers, various types of optical waveguides such as polymer optical waveguides and glass optical waveguides can be used as optical waveguides. Moreover, as an optical circuit device, it can be applied to various optical circuit devices other than silicon photonics.

In addition, the above-mentioned various modifications and modifications of analogous structures can be applied in the same way.

<Fourth Embodiment>
An optical coupling structure according to a fourth embodiment of the invention will be described with reference to FIG.

<Configuration of Optical Coupling Structure>
The optical coupling structure 40 according to the present embodiment differs from the first to third embodiments in that optical circuit devices are connected to each other. Other configurations are substantially the same as those of the first embodiment.

In the optical coupling structure 40, as shown in FIG. 12, one optical circuit device 11 is, for example, silicon photonics, and has a core exposed portion 115 as in the first to third embodiments. In the optical circuit of the core exposed portion 115, the thin silicon wire is formed in a tapered shape. Alternatively, the core exposed portion 115 may have a thin clad protective layer on the upper surface of the optical circuit core 113 .

The other optical circuit device (second optical circuit device) 21 does not have an exposed core portion and is handled in the same way as a normal optical circuit.

The

optical circuit devices

11 and 12 are roughly positioned in advance, and are mounted on an adhesive (not shown) filled between the end surfaces or a holding substrate as necessary. Although the

optical circuit devices

11 and 12 are arranged in contact with each other in this embodiment, the

optical circuit devices

11 and 12 may be arranged apart from each other.

A photocurable resin core 131 is formed by the resin curing light 15 from the second optical circuit device 21, and the resin core 131 is arranged on the exposed core portion 115 (or above the cladding protective layer). A resin clad 132 is filled around it.

Here, the second optical circuit device 21 can use the various optical circuits described above, has an input section (not shown) for the resin curing light 15, and has a core 213 for propagating the resin curing light 15. , the resin curing light 15 is emitted from the emitting end surface.

When ultraviolet light is used as the resin curing light 15, the core 213 of the second optical circuit device 21 is preferably made of a core material transparent to ultraviolet light, such as quartz PLC, polymer circuits, silicon photonics, or InP conductors. Even if it is a wave path, it is preferable to partially have a second core or the like having a structure transparent to resin curing light such as SiON or SiN.

Furthermore, according to the optical coupling structure according to the present embodiment, optical coupling can be achieved through adiabatic coupling between optical circuit devices.

In connecting optical circuit devices by conventional adiabatic coupling, it is necessary to bring the respective cores close to each other. It was difficult to mount, and it was necessary to consider in-plane thickness uniformity such as warping of the optical circuit.

According to this embodiment, the resin core can be satisfactorily formed if the in-plane thickness error is within a predetermined error range. More simply, optical coupling can be achieved by adiabatic coupling through the resin core.

It should be noted that this embodiment can be similarly applied to various modifications and structural changes in the first to third embodiments. In addition, the various modifications described above and modifications of structures that can be analogized can be applied in the same manner.

<Fifth Embodiment>
An optical coupling structure according to a fifth embodiment of the present invention will be described with reference to FIG.

<Configuration of Optical Coupling Structure>
The optical coupling structure 50 according to this embodiment differs from the first to fourth embodiments in that it includes a positioning structure between the optical circuit device and the optical waveguide. Other configurations are the same as those of the first embodiment, and SMF is used for the optical circuit device, the silicon photonics chip, and the optical waveguide. Adiabatic coupling between the resin core in contact with the SMF and the optical circuit realizes highly efficient optical coupling between the SMF and the Si wire.

In the optical coupling structure 50, as shown in FIG. 13, the silicon photonics chip, which is the optical circuit device 11, has a groove 117 capable of accommodating the optical fiber 12 on the optical circuit board 111. FIG. By mounting the optical fiber 12 in the groove 117, the optical fiber core 121 and the optical circuit core 113 are positioned. The optical fiber 12 may be pre-fixed in the groove 117 with an adhesive or the like.

Here, the groove 117 is a U-groove or a V-groove, and has a long configuration in the longitudinal direction (X direction) of the optical circuit core. formed on top. This can be achieved by known trench integration techniques used in passive alignment of silicon photonics chips.

Furthermore, according to the optical coupling structure according to the present embodiment, since the positioning accuracy of the optical circuit core and the optical waveguide core is determined only by the member accuracy, it is possible to realize good optical coupling more easily.

At this time, by using adiabatic bonding via a resin core, it has a mounting tolerance that is several times greater than the positioning accuracy required for butt connection.

For example, in order to obtain an optical coupling efficiency of over 90% with butt splicing, each core positioning accuracy must be sub-micron precision, but with adiabatic coupling, the same degree of optical coupling efficiency can be achieved even if the misalignment is about 2 μm. realizable. As a result, it is possible to relax the manufacturing accuracy of the grooves.

It should be noted that this embodiment can be similarly applied to various modifications and structural changes in the first to fourth embodiments. For example, it can be applied to optical coupling between optical circuit devices other than optical circuit devices and optical waveguides.

<Sixth Embodiment>
An optical coupling structure according to a sixth embodiment of the present invention will be described with reference to FIG.

<Configuration of Optical Coupling Structure>
The optical coupling structure 60 according to this embodiment differs from the first to fifth embodiments in the positioning structure between the optical circuit device and the optical waveguide. Other configurations are the same as those of the first embodiment, and SMF is used for the optical circuit device, the silicon photonics chip, and the optical waveguide 12 . Highly efficient optical coupling between the optical waveguide 12 and the optical circuit device is realized by adiabatic coupling between the resin core in contact with the SMF and the optical circuit.

In the optical coupling structure 60, the silicon photonics chip, which is the optical circuit device 11, is mounted on the electrical mounting substrate 31, as shown in FIG. Here, the surface of the optical circuit on the side of the core and overcladding 114 (the surface opposite to the optical circuit board, hereinafter referred to as "optical circuit surface") faces the upper surface of the electrical mounting board 31, so-called facedown. is implemented in At this time, the distance between the optical circuit core 113 and the electrical mounting board 31 in the board thickness direction (Z direction) is defined by the electrical contact (height determining structure) 32 .

Here, the electrical contact (height-determining structure) 32 is, for example, metal or solder, and can have the same structure as the electrical contact in the known flip-chip connection. Note that electrical wiring and electrical pads are not shown.

Also, the optical fiber 12 is mounted and fixed in a groove (cavity) 311 on the electrical mounting board 31 .

With this configuration, the optical circuit core 113 and the optical waveguide core are positioned in advance only by mechanical accuracy (such as machining accuracy of grooves on the electrical mounting board 31).

Furthermore, according to the optical coupling structure according to the present embodiment, the positioning of the optical circuit core and the optical waveguide core can be determined only by the accuracy of the members, and optical coupling can be realized more easily.

For example, in order to obtain an optical coupling efficiency of over 90% with butt splicing, each core positioning accuracy must be sub-micron precision, but with adiabatic coupling, the same degree of optical coupling efficiency can be achieved even if the misalignment is about 2 μm. realizable. This makes it possible to relax the manufacturing accuracy of the groove, the height determination structure, and the thickness of the electrical contact.

This embodiment can be applied to the connection between optical circuit devices as shown in FIG. 15, and has the same effect. Each optical circuit device 11 is mounted face down on the electrical mounting board 31, and each core position is determined in advance by electrical contacts or a height determination structure.

It should be noted that this embodiment can be similarly applied to various modifications and structural changes in the first to sixth embodiments. For example, in addition to optical circuit devices and optical waveguides, it can also be applied to optical coupling between optical circuit devices.

<Seventh Embodiment>
An optical coupling structure according to a seventh embodiment of the present invention will be described with reference to FIGS. 16A and 16B.

<Configuration of Optical Coupling Structure>
The optical coupling structure 70 according to this embodiment differs from the first to sixth embodiments in the positioning structure between the optical circuit device and the optical waveguide. Other configurations are the same as those of the first embodiment, and SMF is used for the optical circuit device, the silicon photonics chip, and the optical waveguide. Highly efficient optical coupling between the optical waveguide and the optical circuit device is realized by adiabatic coupling between the resin core in contact with the SMF and the optical circuit.

In the optical coupling structure 70, as shown in FIGS. 16A and 16B, the optical fibers, which are the optical waveguides 12, are aligned and fixed by the first holding member 41. FIG.

The first holding part 41 has a hole or groove for accommodating the optical fiber 12, for example a glass block with a V-groove and a lid or a known MT ferrule.

Also, the optical circuit device 11 is mounted and fixed on the second holding component 42 . The mounting of the second holding component 42 and the optical circuit device 11 may be either face-up mounting or the aforementioned face-down mounting.

As shown in FIG. 16B, the first holding component 41 has a positioning structure 43 whose relative position with respect to the optical fiber 12 is defined with high accuracy. As the positioning structure 43, for example, the MT ferrule is provided with two guide pins.

Also, the second holding part 42 is provided with a positioning guide 44 . Here, the positioning guide 44 is, for example, a hole or groove structure into which a guide pin can be fitted.

With this configuration, the positioning structure 43 and the positioning guide 44 fit together, so that the optical circuit core 113 and the optical waveguide core 121 are positioned only with mechanical accuracy.

For example, in order to obtain an optical coupling efficiency of over 90% with butt splicing, each core positioning accuracy must be sub-micron precision, but with adiabatic coupling, the same degree of optical coupling efficiency can be achieved even if the misalignment is about 2 μm. realizable. This makes it possible to relax the manufacturing accuracy of the grooves and the guide pins.

This embodiment can be similarly applied to various modifications and configuration changes in the first to sixth embodiments. For example, in addition to optical circuit devices and optical waveguides, it can also be applied to optical coupling between optical circuit devices.

In the embodiment of the present invention, an example of using an optical fiber or an optical circuit device as an optical component connected to an optical circuit device is shown, but other optical components such as a polymer optical waveguide or a glass optical waveguide may be used.

In the embodiments of the present invention, an example in which the waveguide core and the resin core of the optical component are connected has been shown, but the present invention is not limited to this, and the waveguide core and the resin core of the optical component may be adjacent to each other. It is sufficient that the waveguide core and the resin core can be optically coupled.

In the embodiment of the present invention, an example of the structure, dimensions, materials, etc. of each component is shown in the configuration, manufacturing method, etc. of the optical coupling structure, but the present invention is not limited to this. Any material may be used as long as it exhibits the function of the optical coupling structure and produces an effect.

The present invention relates to an optical coupling structure of optical components, and can be applied to devices and systems such as optical communication.

10 Optical Coupling Structure 11 Optical Circuit Device 113 Optical Circuit Core 112 Overcladding 115 Core Exposed Portion 12 Optical Component (Optical Waveguide)
121 waveguide core 131 resin core 14 photocurable resin

Claims

an optical circuit device having an optical circuit core and an overcladding;
an optical component having a waveguide core;
a resin core that is cured by irradiating a photocurable resin with light;
The optical circuit device has a core exposed portion where the optical circuit core is exposed,
The optical coupling structure, wherein the resin core is arranged so as to be optically coupled with the exposed core portion, and is connected to or close to the waveguide core.
an optical circuit device having an optical circuit core and an overcladding;
an optical component having a waveguide core;
a resin core that is cured by irradiating a photocurable resin with light;
A part of the overcladding on the side where the optical component is arranged is thin,
The optical coupling structure, wherein the resin core is arranged so as to be optically coupled with the optical circuit core under the part of the overcladding, and is connected to or close to the waveguide core.
3. The optical coupling structure according to claim 1, further comprising a resin clad having a refractive index lower than that of the resin core around the resin core.
the optical component is an optical fiber,
The optical circuit device is provided with a groove elongated in the longitudinal direction of the optical circuit core,
The optical coupling structure according to any one of claims 1 to 3, wherein the optical fiber is accommodated in the groove.
the optical component is an optical fiber,
the optical circuit device;
An electrical mounting board on which the optical fiber is mounted,
the optical circuit surface of the optical circuit device and the upper surface of the electrical mounting board are opposed and fixed in contact with each other;
4. The optical fiber is mounted in a groove hardened in the electrical mounting board, and the core of the optical fiber and the optical circuit core are positioned. The optical coupling structure according to .
The optical component is another optical circuit device,
an electrical mounting board on which the optical circuit device and the other optical circuit device are mounted;
the respective optical circuit surfaces of the optical circuit device and the other optical circuit device and the surface of the electrical mounting board face each other and are fixed in contact;
4. The optical coupling structure according to any one of claims 1 to 3, wherein the optical circuit core and the core of the other optical circuit device are positioned.
a first holding component on which the optical component is mounted;
a second holding component on which the optical circuit device is mounted;
The optical coupling structure according to any one of claims 1 to 6, further comprising a positioning mechanism that positions and fixes the first holding part and the second holding part.
A method for manufacturing an optical coupling structure between an optical circuit device having an optical circuit core and an overcladding and an optical component having a waveguide core,
a step of exposing the optical circuit core and forming a core exposed portion in the optical circuit device by removing part of the overcladding or partially leaving the overcladding unformed;
arranging and positioning the optical circuit device and the optical component;
applying an uncured photocurable resin to the core exposed portion;
a step of inputting resin curing light from the waveguide core and irradiating the photocurable resin to form a resin core;
and forming a resin clad around the resin core.
A method for manufacturing an optical coupling structure between an optical circuit device having an optical circuit core and an overcladding and an optical component having a waveguide core,
thinning a portion of the overcladding on the side where the optical component is arranged in the optical circuit device;
arranging and positioning the optical circuit device and the optical component;
applying an uncured photocurable resin to a portion of the overcladding;
a step of inputting resin curing light from the waveguide core and irradiating the photocurable resin to form a resin core;
and forming a resin clad around the resin core.
A method for manufacturing an optical coupling structure between an optical circuit device having an optical circuit core and an overcladding and an optical component having a waveguide core,
a step of exposing the optical circuit core and forming a core exposed portion in the optical circuit device by removing part of the overcladding or partially leaving the overcladding unformed;
forming a thin clad layer on the core exposed portion;
arranging and positioning the optical circuit device and the optical component;
applying an uncured photocurable resin to the thin cladding layer;
a step of inputting resin curing light from the waveguide core and irradiating the photocurable resin to form a resin core;
and forming a resin clad around the resin core.